The rotor has a claw pole structure comprising magnetised parts, and an annular excitation winding which is positioned around the rotating shaft of the machine. The rotor is formed by two pole wheels which each comprise claw poles each of which is inserted between two claw poles of the opposite pole wheel.
The magnets which are arranged between two claw poles serve to prevent the leakage of magnetic flux between the magnetic poles in claw form. The magnets may be positioned between each pair of claw poles or between only certain pairs of claw poles.
The magnets are positioned between the claw poles of each pole wheel either by clips or by means of two grooves which are made in individual lateral edges of the claw poles between which the magnet is situated.
In the first case the magnets have a tendency to move as a result of centrifugal force because the clips do not ensure that they are fixed in place in the optimum way.
In the second case the magnets have to fill the whole of the interpole space, which increases the cost of the machine because these magnets are expensive.
The object of the invention is to propose a rotor having interpole magnets which are both reduced in size and fixed in place in the lateral grooves in the claw poles, i.e. by using the grooves which are made as a normal practice by a standard milling operation and hence without changing the usual process by which the magnet-equipped rotor is produced.